Process Optimization for the Extraction of Polyphenols from Okara

The objective of the present investigation is to examine okara, a suitable substrate for polyphenol extraction, and to develop a feasible eco-friendly process to maximize the yield of antioxidant phenolics. Box-Behnken design (BBD) based on response surface methodology (RSM) was employed to investigate the effect of temperature (°C), solvent fraction (%) and incubation time (min) on polyphenol extraction by using MINITAB 15 software. Acetone was used as solvent to extract the phenolic compounds possessing the antioxidant properties (DPPH radical scavenging activity, reducing power, and metal chelating activity). Extraction under the optimum conditions yielded total polyphenolic content of 1.16 mg/mL, DPPH radical scavenging activity of 61.07 %, metal chelating activity of 61.20 % and better reducing power. The effective model developed for antioxidant mining from okara under mild operational conditions can be a valuable technique for soybean-based food industry.